* [Cluster-devel] [GFS2 PATCH] GFS2: Don't waste time locking lru_lock for non-lru glocks [not found] <842931352.34658265.1501085354071.JavaMail.zimbra@redhat.com> @ 2017-07-26 16:10 ` Bob Peterson 2017-07-26 16:11 ` Steven Whitehouse 0 siblings, 1 reply; 2+ messages in thread From: Bob Peterson @ 2017-07-26 16:10 UTC (permalink / raw) To: cluster-devel.redhat.com Hi, Before this patch, glock_dq would call gfs2_glock_remove_from_lru. For glocks that are never put on the LRU, such as the transaction glock, this just takes the spin_lock, determines there's nothing to be done because the list is empty, then unlocks again. This was causing unnecessary lock contention on the lru_lock spin_lock. This patch adds a check for GLOF_LRU in the glops before taking the spin_lock, thus reducing lru_lock contention. Signed-off-by: Bob Peterson <rpeterso@redhat.com> --- diff --git a/fs/gfs2/glock.c b/fs/gfs2/glock.c index c38ab6c81898..1029340fc8ba 100644 --- a/fs/gfs2/glock.c +++ b/fs/gfs2/glock.c @@ -150,6 +150,9 @@ void gfs2_glock_add_to_lru(struct gfs2_glock *gl) static void gfs2_glock_remove_from_lru(struct gfs2_glock *gl) { + if (!(gl->gl_ops->go_flags & GLOF_LRU)) + return; + spin_lock(&lru_lock); if (!list_empty(&gl->gl_lru)) { list_del_init(&gl->gl_lru); ^ permalink raw reply related [flat|nested] 2+ messages in thread
* [Cluster-devel] [GFS2 PATCH] GFS2: Don't waste time locking lru_lock for non-lru glocks 2017-07-26 16:10 ` [Cluster-devel] [GFS2 PATCH] GFS2: Don't waste time locking lru_lock for non-lru glocks Bob Peterson @ 2017-07-26 16:11 ` Steven Whitehouse 0 siblings, 0 replies; 2+ messages in thread From: Steven Whitehouse @ 2017-07-26 16:11 UTC (permalink / raw) To: cluster-devel.redhat.com Hi, Looks good. Acked-by: Steven Whitehouse <swhiteho@redhat.com> Steve. On 26/07/17 17:10, Bob Peterson wrote: > Hi, > > Before this patch, glock_dq would call gfs2_glock_remove_from_lru. > For glocks that are never put on the LRU, such as the transaction > glock, this just takes the spin_lock, determines there's nothing to > be done because the list is empty, then unlocks again. This was > causing unnecessary lock contention on the lru_lock spin_lock. > This patch adds a check for GLOF_LRU in the glops before taking > the spin_lock, thus reducing lru_lock contention. > > Signed-off-by: Bob Peterson <rpeterso@redhat.com> > --- > diff --git a/fs/gfs2/glock.c b/fs/gfs2/glock.c > index c38ab6c81898..1029340fc8ba 100644 > --- a/fs/gfs2/glock.c > +++ b/fs/gfs2/glock.c > @@ -150,6 +150,9 @@ void gfs2_glock_add_to_lru(struct gfs2_glock *gl) > > static void gfs2_glock_remove_from_lru(struct gfs2_glock *gl) > { > + if (!(gl->gl_ops->go_flags & GLOF_LRU)) > + return; > + > spin_lock(&lru_lock); > if (!list_empty(&gl->gl_lru)) { > list_del_init(&gl->gl_lru); > ^ permalink raw reply [flat|nested] 2+ messages in thread
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2017-07-26 16:10 ` [Cluster-devel] [GFS2 PATCH] GFS2: Don't waste time locking lru_lock for non-lru glocks Bob Peterson
2017-07-26 16:11 ` Steven Whitehouse
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